Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Department of Medical Research, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Sci Rep. 2021 May 11;11(1):9924. doi: 10.1038/s41598-021-89336-8.
The purpose of present study was to longitudinally investigate the alterations in infrapatellar fat pad (IPFP) vascularity in 5/6 nephrectomized rats by using dynamic contrast enhanced (DCE) MRI and IPFP degeneration by using MRI T2* relaxation time. Twelve male Sprague-Dawley rats were assigned to a control group and a 5/6 nephrectomy CKD group. The right knees of all rats were longitudinally scanned by 4.7 T MRI, and serial changes in the IPFP were assessed at 0, 8, 16, 30, and 44 weeks by DCE-MRI (parameters A, k and k) and MRI T2* mapping. After MRI measurements, knee specimens were obtained and evaluated histologically. The CKD group had IPFPs with lower blood volume A and lower permeability k values from 16 weeks (p < 0.05), lower venous washout k value from 30 weeks (p < 0.001), and significantly higher T2* values reflecting adipocyte degeneration beginning at 16 weeks (p < 0.05). The histopathological results confirmed the MRI findings. Hypoperfusion and adipocytes degeneration related to CKD were demonstrated in a rodent 5/6 nephrectomy model. DCE parameters and MRI T2* can serve as imaging biomarkers of fat pad degeneration during CKD progression.
本研究旨在通过动态对比增强（DCE）MRI 对 5/6 肾切除大鼠髌下脂肪垫（IPFP）血管变化进行纵向研究，并通过 MRI T2弛豫时间对 IPFP 退变进行研究。将 12 只雄性 Sprague-Dawley 大鼠分为对照组和 5/6 肾切除 CKD 组。所有大鼠的右膝关节均在 4.7T MRI 上进行纵向扫描，并通过 DCE-MRI（参数 A、k 和 k）和 MRI T2映射在 0、8、16、30 和 44 周时对 IPFP 的进行连续评估。MRI 测量后，获得膝关节标本并进行组织学评估。CKD 组从 16 周开始，IPFP 的血容量 A 和渗透性 k 值较低（p<0.05），静脉洗脱 k 值从 30 周开始较低（p<0.001），反映脂肪细胞退变的 T2值从 16 周开始显著升高（p<0.05）。组织病理学结果证实了 MRI 发现。在大鼠 5/6 肾切除模型中证实了与 CKD 相关的低灌注和脂肪细胞退变。DCE 参数和 MRI T2可以作为 CKD 进展过程中脂肪垫退变的影像学生物标志物。
